A Ukrainian who testified in the Russian trial of filmmaker Oleh Sentsov and later recanted his testimony has been transferred to a harsh punishment cell and is being denied medical care despite worsening health.

Hennadiy Afanasyev's lawyer told RFE/RL that Afanasyev, who is serving a seven-year prison sentence after being convicted on charges widely seen as fabricated, had requested a transfer to another facility so he could get treatment for a blood infection, but that has been rejected.

Earlier this month, they moved him to a punishment cell, his lawyer, Aleksandr Popkov, said, after allegedly finding contraband items including a phone SIM card and, earlier, a razor blade. Afanasyev denied the items were his. 

"They’re seriously squeezing him," Popkov said. "They’re using the full power of the repressive machine against him. This, most likely, worries him most. One thing after another is piling up: problems with his health, problems with the [prison] director, who is reprimanding him without cause."

Afanasyev was arrested in Crimea in May 2014, along with Sentsov and two other men, and was accused of being part of a terrorist conspiracy on the Black Sea peninsula, which had been annexed by Russia two months earlier. 

Afanasyev initially provided testimony that helped convict Sentsov and his co-defendant Oleksandr Kolchenko. But he later retracted his statement, saying he had been tortured by Russian security agents. He was sentenced in December 2014 by a Moscow court, and sent to a prison colony in the northern Russian region of Komi. 

Senstov, who received international acclaim for his 2011 film Gamer, stopped his filmmaking in late 2013 as protests in Kyiv against Ukrainian President Viktor Yanukovych began to build. Those protests later culminated in violent clashes that sent Yanukovych fleeing the country in February 2014. 

Sentsov later helped bring food and water to Ukrainian soldiers who had been barricaded in their bases in Crimea after Russia's stealthy takeover of the peninsula. 

He was accused of organizing the firebombing of pro-Russia organizations on the peninsula and was sentenced to 20 years in prison

Popkov said Afanasyev had also been barred from receiving telephone calls, and relatives reported he hadn't been receiving mail since December. 

With reporting by Igor Bubnov of RFE/RL's Russian Service